Retrospective Investigation of Cataract Management in Avian Species in a Zoologic Collection

Abstract

A review of avian cataracts at the Wildlife Conservation Society's Bronx Zoo between 1992 and 2011 was conducted. Ninety cataracts in 54 birds from 42 species were identified. Cataracts were found primarily during examination for ocular abnormalities (29/54, 53.7%) or opportunistically (13/54, 24.1%) and were most commonly diagnosed as mature (22/90, 24.4%). Systemic medical conditions diagnosed in these birds included West Nile virus (4/54, 7.4%), head trauma (3/54, 5.6%), plumbism and Salmonella Pullorum (1/54, 1.9%), Marek's disease (1/54, 1.9%), leukocytosis (1/54, 1.9%), and hyperglycemia (1/54, 1.9%). Cataracts were progressive in seven birds of four species. Unilateral enucleation was performed in 2/54 (3.7%) birds, and 12/54 (22.2%) underwent cataract removal (phacoemulsification in 16 eyes and standard extracapsular cataract extraction in 2 eyes). Concurrent ocular abnormalities, such as corneal scarring and lens-induced uveitis, were seen in 2/18 (11.1%) eyes preoperatively in the group undergoing cataract removal, 2/2 (100%) eyes preoperatively in the group undergoing enucleation, and 33/70 (47.1%) of eyes that did not undergo surgery. For birds undergoing cataract removal, complications included successfully treated cardiorespiratory arrest intraoperatively (1/12, 8.3%) as well as postanesthetic complications of acute respiratory distress and tracheal stricture (2/12, 16.7%). The most common postoperative ocular abnormalities included posterior capsular opacity (4/18 eyes, 22.2%) and corneal scarring (2/18 eyes, 11.1%). Lens cortical regrowth and marked posterior lens capsular opacity occurred in one eye of one bird after phacoemulsification, necessitating a second ocular surgery. A successful outcome, as determined by improved postoperative visual acuity, was seen in 10/12 (83.3%) birds undergoing cataract removal, and 5/12 (41.7%) of these birds were alive >3 yr after surgery. The results of this review will aid clinicians in identifying common stages of cataracts, determining eligibility for cataract surgery, and managing postoperative complications in avian patients.

Long‐term outcome of phacoemulsification in raptors—A retrospective study (1999‐2014)

“…Lenticular changes were documented in 12.6% and 34% of free‐living, mixed age, North American raptors presented to a wildlife clinic and adult captive‐born screech owls, respectively. Ninety cataracts in 54 birds of multiple species were reported in a zoo avian population of which 53.7% (29/54) of those birds were examined specifically because of an ocular abnormality, such as cloudiness, difficulty navigating the enclosure, or blindness . In an adult, captive bald eagle population, cataracts were seen in eight eyes of 10 eagles .…”

“…Cataract removal has been reported in a variety of avian species . Techniques, results, and postoperative follow‐up vary between reports.…”

“…IOL placement was reported in one great‐horned owl . Reported complications of phacoemulsification in birds include anterior uveitis, ocular hypertension and glaucoma, fibropupillary membranes (FPM), synechiae, iris bombé, corneal ulceration, corneal edema, posterior capsular opacity (PCO), retinal degeneration, retinal detachment, retained lens cortex, and infectious endophthalmitis . The purpose of this study is to report long‐term follow‐up in a series of seven nonreleasable raptors that underwent phacoemulsification at the University of Tennessee between 1999 and 2014.…”

“…Ninety cataracts in 54 birds of multiple species were reported in a zoo avian population of which 53.7% (29/54) of those birds were examined specifically because of an ocular abnormality, such as cloudiness, difficulty navigating the enclosure, or blindness. 4 In an adult, | 361 SIGMUND et al…”

“…2,3,[5][6][7] Cataract removal has been reported in a variety of avian species. 4,[8][9][10][11] Techniques, results, and postoperative followup vary between reports. The largest report by Rainwater et al, described cataract surgery in 18 eyes of 12 birds from 10 species.…”